1. Field of the Invention
The present invention relates to a developing apparatus for converting an electrostatic latent image to a visible image and to an image forming apparatus using the inventive developing apparatus. The present invention also relates to a method of supplying toner in an image forming apparatus.
2. Discussion of the Background
In the image forming apparatus to which the electrophotographic copying method is applicable such as copying machine, facsimile device, or printer, a developing process of supplying toner employed as developer (i.e., a developing agent) (hereinafter, "toner") to an electrostatic latent image formed on the image carrier, such as a photosensitive body is performed. The electrostatic latent image is converted to a visible image.
The developing apparatus employed in the developing process is constructed with a developing sleeve opposing the image carrier in the developing tub and supplying the toner carried on the surface thereof to the image carrier. A toner replenishing part is mounted on the developing tub and contains unused toner in the interior of the developing tub.
In the developing apparatus, visible image treatment for the electrostatic latent image (i.e., the developing process) is performed by electrostatically absorbing toner carried on the developing sleeve by the action of the electrostatic attraction force of the electrostatic latent image formed on the image carrier. When the amount of the toner contained in the developing tub becomes insufficient, the toner is replenished from the toner replenishing part.
The toner replenishing part is provided with, for instance, a container (such as a bottle, a hopper, etc.) containing unused toner in the interior thereof and disposed such that the opening thereof is directed downward. By driving the toner replenishing member installed on the opening part, the necessary (or required) amount of the toner is replenished to the developing tub.
Here, the toner contained in the toner replenishing part has a comparatively strong attraction force between the toner particles, and the toner is apt to be solidified in the container. When the toner is solidified therein, only a part of the solidified toner is peeled off in the container, and the other part thereof remains solidified in the container, and thus, all toner cannot be replenished on some occasions.
Furthermore, even though the toner slips down in the container, the solidified toner may set into the developing tub and/or cause the exhaust opening to become clogged with the solidified toner.
In order to solve such troublesome matters, a vibration is applied to the toner discharged from the container, and the toner is broken into pieces and/or pulverized. As a result, the toner is dispersed uniformly and supplied into the developing tub. Such structure is disclosed, for instance, in the published specification of the Japanese Laid-Open Patent Publication No. 6-222672/1994. Or otherwise, the bottle is rotated and pulsed so that the toner contained in the developing tub is demolished by an agitating member disposed therein.
Such structure is disclosed, for instance, in the published specification of the Japanese Laid-open Utility Model Publication No. 6-69961/1994.
However, according to the former structure, the solidification of the toner contained in the bottle or the hopper cannot be eliminated, while, according to the latter structure, there arises a new problem that it is necessary to further prepare a special structure for equipping the bottle with the agitating member and/or controlling the rotation of the bottle.